1. Field of the Invention
The present invention relates to a moving-target tracking apparatus wherein an original picture image, which consists of a plurality of frames sequentially continued, photographed with a scene including at least one moving target, is inputted and a moving-target projected on the original picture image is tracked.
2. Description of the Related Art
For example, it is desired nowadays that there appears, for example, an apparatus capable of implementing such a matter that on a dynamic picture image obtained through photographing the state of a soccer game in a wide field, a specified soccer player, who is designated from among a plurality of soccer players playing the soccer game, is tracked.
Hitherto, there already exists several types of apparatus in which a result of tracking of the moving target, for example, the above-mentioned soccer player, is displayed on a dynamic picture image. Those apparatuses are, however, for processing a photographed-state dynamic picture image through a software on an off-line basis, and take a lot of time for processing. Thus, those apparatuses are of no use at all in the event that such an operational ability on a real-time basis that a dynamic picture image is photographed and immediately after a specified player is tracked is needed. Further, in such a scene that a specified player is tracked in the soccer game as mentioned above, the specified player will be changed on the photographed picture image in such a manner that the player runs, stops, changes in direction, falls down, etc. Thus, according to the earlier developed apparatuses, the complete tracking of the player as a target is impossible even with the off-line processing, and as a result there is a need to conduct a manual tracking by an operator with respect to an aided tracking impossible section. This will be associated with a problem that a complete automation is not implemented.
Recently, as a moving-target tracking scheme regarding an operational ability on a real-time basis as important, there has been developed a scheme according to a template matching based on the correlation operation. According to this scheme, restricting a search area to a local area makes it possible to an amount of calculations, and it is possible to perform the processing on a parallel basis in view of the principle of the calculation.
According to this scheme, however, a template is made up beforehand, and a correlation operation with the template made up beforehand is simply performed. Thus, this scheme has such a weak point that it is easy to lose sight of a target, such as the player of the above-mentioned soccer game, which will be deformed with great amount on the picture image, and while the operational ability on a real-time basis is improved, it is not satisfactory in the tracking performance.
With respect to an adoption of types of information for tracking, there has been made various proposals, for example, a proposal (Japanese Patent Application Laid Open Gazette Hei. 8-130675) which says that it is recommended that color information is used to determine a movement vector, a proposal (Japanese Patent Application Laid Open Gazette Sho. 60-209104) which says that it is recommended that a differential image, which is obtained by spatially differentiating an image provided for a usual observation, is used to perform a correlation operation, and a proposal (Japanese Patent Application Laid Open Gazette Sho. 60-195682) which says that it is recommended that information as to the past motion of the target to be tracked is used to predict the subsequent motion of the target. However, none of those proposals satisfies requirements of both an operational ability on a real-time basis and a tracking performance sufficient for practical use.